Valve actuator

ABSTRACT

A valve actuator includes: a motor and a gear assembly transmitting a driving force of the motor to a ball valve. The gear assembly includes: an input gear coupled to a rotational shaft of the motor and rotating with the rotational shaft, an output gear spaced apart from the input gear, coupled to a stem of the ball valve, and transmitting a rotational force of the input gear to the stem, and a power transmission gear transmitting the rotational force of the input gear to the output gear and including a first gear set disposed between the input gear and the output gear. The first gear set includes a clutch shaft moving in a vertical direction, and a first gear and a second gear that are coupled to the clutch shaft and, based on vertical movement of the clutch shaft, disengage from or couple to each other.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2022-0064877, filed in the Korean IntellectualProperty Office on May 26, 2022.

TECHNICAL FIELD

The present disclosure relates to a valve actuator for opening andclosing a refrigerant, and more particularly, to a valve actuator havinga gear assembly having a novel structure.

BACKGROUND

Refrigerants play a crucial role in air conditioners, which are integralto air conditioning systems. However, the conventional refrigerants,ranging from the first to third generation, have exhibited significantozone layer depletion potential (ODP) and/or global warming potential(GWP).

In response to these concerns, efforts have made in recent years todevelop fourth-generation refrigerants that possess reduced ozonedepletion potential and/or global warming potential. However, thesenewly developed refrigerants, such as hydrogen fluoroolefin (HFO)-basedrefrigerants, come with certain drawbacks. They tend to be moreexpensive than conventional refrigerants, and they also carry risk offlammability, which increases the potential for fire hazards andexplosions.

Therefore, an air conditioning system including a ball valve forblocking refrigerant leakage is introduced.

The ball valve may include a ball in which a flow path is formed, a pipeinto which the ball is inserted, a tap part provided in the pipe, and astem installed in the tap part.

The ball valve can open and close the refrigerant by rotating the stem,and the air conditioning system may be provided with a valve actuatorthat is operated by an electrical signal received from the outside toblock and operate the ball valve.

The valve actuator may not have a separate manual rotation mode or mayhave a manual rotation mode by applying a motor capable of reverserotation.

The valve actuator may have a clutch unit used in the manual rotationmode and installed on the output shaft of the gear assembly.

For example, in the valve actuator, the gear train is disengaged whenthe output shaft (valve rotation shaft) is pressed in the axialdirection, and after rotating the valve in this state, if pressing ofthe output shaft is disengaged, the position of the output shaft returnsto its original position by the return spring.

Therefore, the conventional valve actuator can have a problem in thatsealing performance may be deteriorated because the output shaft movesin two directions, i.e., a rotational direction and an axial direction(a vertical direction), and there can be a problem in that the size ofthe product may increase because the output shaft must move in the axialdirection in the manual rotation mode.

In addition, a strong and large return spring is required to return theoutput shaft to its original position, and since the engagement betweengear teeth is directly disengaged in the manual rotation mode, there canbe a problem that the gear teeth may be adversely affected.

SUMMARY

The present disclosure is directed to a valve actuator capable ofsolving at least one of the above problems, among others.

According to one aspect of the subject matter described in thisapplication, a valve actuator can include a housing defining an innerspace, a motor disposed in the inner space of the housing, and a gearassembly disposed in the inner space of the housing and configured totransmit, to a ball valve, a driving force of the motor. The gearassembly can includes an input gear coupled to a rotational shaft of themotor and configured to rotate with the rotational shaft, an output gearspaced apart from the input gear in a horizontal direction, coupled to astem of the ball valve, and configured to transmit a rotational force ofthe input gear to the stem, and a power transmission gear configured totransmit the rotational force of the input gear to the output gear. Thepower transmission gear can include a first gear set disposed betweenthe input gear and the output gear. The first gear set can include aclutch shaft disposed in the housing and configured to move in avertical direction, and a first gear and a second gear that are coupledto the clutch shaft and that are configured to, based on verticalmovement of the clutch shaft, disengage from or couple to each other.

Implementations according to this aspect can include one or more of thefollowing features. For example, the first gear can provide a couplingpart configured to couple the first gear to the second gear andprotruding from a lower surface of the first gear coupled to the inputgear, and an upper surface of the second gear can provide a couplingpart insertion groove into which the coupling part of the first gear isinserted.

In some examples, the clutch shaft can provide a push-up part that isconfigured to push the first gear upward by contacting the coupling partof the first gear and that is positioned in a push-up part insertiongroove provided at a lower surface of the coupling part of the firstgear. In some examples, the housing can include a lower case, an uppercase coupled to the lower case, and a middle plate positioned in a spacedefined by the lower case and the upper case. The motor and the gearassembly can be disposed in a space defined by the middle plate and thelower case.

In some implementations, the first gear can be configured to move towardthe second gear by a return spring disposed between the first gear andthe middle plate. In some examples, the valve actuator can furtherinclude a snap ring disposed at the clutch shaft and between the returnspring and an upper surface of the first gear.

In some implementations, the valve actuator can further include a sealring disposed at the clutch shaft and below the second gear. The lowercase can provide a guide groove at which the clutch shaft is coupled andconfigured to, based on the clutch shaft moving in the verticaldirection, allow the seal ring to move in the vertical direction withthe clutch shaft. In some examples, a movement distance of the clutchshaft in an upward direction can be based on a gap between the seal ringand the second gear.

In some implementations, the power transmission gear can further includea second gear set disposed adjacent to the first gear set in thehorizontal direction, and the second gear set can include a third gearcoupled to the first gear, and a fourth gear disposed above the thirdgear, configured to rotate with the third gear, and coupled to theoutput gear. In some examples, the motor and the third gear can beconfigured to, based on the clutch shaft moving upward, limit an upwardmovement of the second gear.

According to another aspect of the subject matter described in thisapplication, a valve actuator can include: a housing defining an innerspace, a motor disposed in the inner space of the housing, and a gearassembly disposed in the inner space of the housing and configured totransmit, to a ball valve, a driving force of the motor. The gearassembly can include an input gear coupled to a rotational shaft of themotor and configured to rotate with the rotational shaft, an output gearspaced apart from the input gear in a horizontal direction, coupled to astem of the ball valve, and configured to transmit a rotational force ofthe input gear to the stem, and a power transmission gear configured totransmit the rotational force of the input gear to the output gear. Thepower transmission gear can include a first gear set and a second gearset disposed between the input gear and the output gear and arrangedalong the horizontal direction.

Implementations according to this aspect can include one or more of thefollowing features. For example, the first gear set can include a clutchshaft disposed in the housing and configured to move in a verticaldirection, and a first gear and a second gear that are coupled to theclutch shaft and that are configured to, based on vertical movement ofthe clutch shaft, disengage from or couple to each other.

In some examples, the first gear can provide a coupling part configuredto couple the first gear to the second gear and protruding from a lowersurface of the first gear coupled to the input gear, and an uppersurface of the second gear can provide a coupling part insertion grooveinto which the coupling part of the first gear is inserted. In someexamples, the clutch shaft can provide a push-up part that is configuredto push the first gear upward by contacting the coupling part of thefirst gear and that is positioned in a push-up part insertion grooveprovided at a lower surface of the coupling part of the first gear.

In some implementations, the housing can include a lower case, an uppercase coupled to the lower case, and a middle plate positioned in a spacedefined by the lower case and the upper case. The motor and the gearassembly can be disposed in a space defined by the middle plate and thelower case. In some examples, the first gear can be configured to movetoward the second gear by a return spring disposed between the firstgear and the middle plate.

In some implementations, the valve actuator can further include a snapring disposed at the clutch shaft and between the return spring and anupper surface of the first gear. In some implementations, the valveactuator can further include a seal ring disposed at the clutch shaftand below the second gear, the lower case can provide a guide groove atwhich the clutch shaft is coupled and configured to, based on the clutchshaft moving in the vertical direction, allow the seal ring to move inthe vertical direction with the clutch shaft.

In some examples, a movement distance of the clutch shaft in an upwarddirection can be based on a gap between the seal ring and the secondgear. In some examples, the second gear set can include a third gearcoupled to the first gear, and a fourth gear disposed above the thirdgear, configured to rotate with the third gear, and coupled to theoutput gear. The motor and the third gear can be configured to, based onthe clutch shaft moving upward, limit an upward movement of the secondgear.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a valve actuator and aball valve that are assembled.

FIG. 2 is a diagram illustrating an exploded perspective view of anexample of main parts of FIG. 1 , as viewed from above.

FIG. 3 is a diagram illustrating an exploded perspective view of anexample of main parts of FIG. 1 , as viewed from bottom.

FIG. 4 is a diagram illustrating a cross-sectional view of an example ofa flange.

FIG. 5 is a diagram illustrating an example of a gear assembly in whicha first gear and a second gear coupled to a clutch shaft aredisassembled, as viewed from above.

FIG. 6 is a diagram illustrating an example of a gear assembly in whicha first gear and a second gear coupled to a clutch shaft aredisassembled, as viewed from above.

FIG. 7 is a diagram illustrating a cross-sectional view of an example ofa state in which an output shaft of a gear assembly is assembled to ahousing and a flange.

FIG. 8 is a diagram illustrating a cross-sectional view of an example ofa state in which a clutch shaft, first gear, and second gear of a gearassembly are assembled to a housing.

FIG. 9 is a diagram illustrating a cross-sectional view of an example ofa state in which a clutch shaft of a gear assembly is pressed.

FIG. 10 is a diagram illustrating a cross-sectional view of an exampleof a state in which an adhesive is applied to a power line passage holeof a housing.

DETAILED DESCRIPTION

FIG. 1 is a diagram illustrating an example of a valve actuator and aball valve that are assembled, FIG. 2 is a diagram illustrating anexploded perspective view of an example of main parts of FIG. 1 , asviewed from above, and FIG. 3 is a diagram illustrating an explodedperspective view of an example of main parts of FIG. 1 , as viewed fromthe bottom.

FIG. 4 is a diagram illustrating a cross-sectional view of an example ofa flange, FIG. 5 is a diagram illustrating an example of a gear assemblyin which a first gear and a second gear coupled to a clutch shaft aredisassembled, as viewed from above, and FIG. 6 is a diagram illustratingan example of a gear assembly in which a first gear and a second gearcoupled to a clutch shaft are disassembled, as viewed from above.

FIG. 7 is a diagram illustrating a cross-sectional view of an example ofa state in which an output shaft of a gear assembly is assembled to ahousing and a flange, and FIG. 8 is a diagram illustrating across-sectional view of an example of a state in which a clutch shaft,first gear, and second gear of a gear assembly are assembled to ahousing.

FIG. 9 is a diagram illustrating a cross-sectional view of an example ofa state in which a clutch shaft of a gear assembly is pressed, and FIG.10 is a diagram illustrating a cross-sectional view of an example of astate in which an adhesive is applied to a power line passage hole of ahousing.

A ball valve 10 provided in the air conditioning system to blockrefrigerant leakage includes a ball in which a flow path is defined, apipe 12 into which the ball is inserted, a tap part 14 provided in thepipe 12, and a stem 16 installed on the tap part 14.

In some implementations, to install a valve actuator on the tap part 14of the standardized ball valve 10, the valve actuator can include aflange 20 screwed to the tap part 14 of the ball valve 10 but coupled toa housing 30 of the valve actuator by a fastening member such as a screwor bolt.

In some implementations, the valve actuator can be additionallyinstalled to the ball valves 10 of various standards already provided inthe field. For example, according to the structure in which the flange20 is provided separately from the ball valve 10 and the housing 30 andcoupled to the ball valve 10 and the housing 30 by a separate fasteningmember or a separate fastening method, the valve actuator can beadditionally installed to the ball valves 10 of various standardsalready provided in the field.

The flange 20 can have a tap part insertion hole 22 in which a tap part21 screwed with the tap part 14 of ball valve is provided on an innersurface.

In some implementations, a stem insertion hole 23 communicating with thetap part insertion hole 22 and into which the stem 16 of the ball valve10 is inserted, and a plurality of long holes 24 positioned at a certaindistance from the center of the tap part insertion hole 22 and formedlong in the circumferential direction can be further provided.

In some implementations, the flange 20 has a chamfer 25 defined at theinner surface of the tap part insertion hole 22.

In some implementations, a chamfer 15 having a shape corresponding tothe chamfer 25 of the flange 20 is provided at the top of the tap part14 of the ball valve 10.

For example, in a state where the flange 20 is screwed to the tap part14 of the ball valve 10, the chamfer 25 of the flange 20 is in contactwith the chamfer 15 provided at the upper end of the tap part 14 of theball valve 10.

In some implementations, a supporting reaction force can be generated bythe chamfers 15 and 25 in contact with each other in a state where theflange 20 is screwed to the tap part 14 of the ball valve 10.

In this regard, even if the valve turning torque is greater than thescrew fastening force between the tap part 21 of the flange 20 and thetap part 14 of the ball valve 10, loosening between the tap part 21 ofthe flange 20 and the tap part 14 of the ball valve 10 can besuppressed, and the assembly state between the tap part 21 of the flange20 and the tap part 14 of the ball valve 10 can be maintained.

In some implementations, when screwing the tap part 21 of the flange 20to the tap part 14 of the ball valve 10, even if the starting point ofthe thread formed in the tap part 14 of the ball valve 10 is notconstant, the tap part 21 of the flange 20 can be screwed to the tappart 14 of the ball valve 10.

The flange 20 can further include a ring insertion groove 26 defined atthe upper surface and in which a second seal ring R2 is disposed

In some implementations, a minute gap provided between the flange 20 anda flange coupling part 34 can block moisture from entering the inside ofthe housing 30.

The housing 30 can define a space in which a motor 40 and a gearassembly 100 provided in the valve actuator are received.

The housing 30 can include a lower case 31, an upper case 32 coupled tothe lower case 31, a middle plate 33 positioned in an inner spaceprovided by the lower case 31 and the upper case 32, and a flangecoupling part 34 provided on the lower case 31 and coupled to the flange20.

In some implementations, the motor 40 and the gear assembly 100 may bedisposed in a space provided by the middle plate 33 and the lower case31 and will be described below in further detail.

In some implementations, the motor 40 may be disposed in a spaceprovided by the middle plate 33 and the upper case 32, such that thearrangement of the plurality of gears provided in the gear assembly 100may be different.

The flange coupling part 34 of the housing 30 can have a plurality ofcircular grooves 34 a into which a plurality of fastening members 50passing through the plurality of long holes 24 can be fastened,respectively.

Each of the plurality of long holes 24 can communicate with at least oneof the plurality of circular grooves 34 a.

In some implementations, a number of the plurality of circular grooves34 a may be twice or more than a number of the plurality of long holes24.

In this regard, when the number of the plurality of circular grooves 34a is twice or more than the number of the plurality of long holes 24,when the flange 20 is screwed to the tap part 14 of the ball valve 10,even if a starting point of the thread defined at the tap part 14 of theball valve 10 is not constant, the flange 20 can be screwed into the tappart 14 of the ball valve 10.

In some implementations, the number of the plurality of circular grooves34 a can be same as the number of the plurality of long holes 24.

In some implementations, the number of the plurality of circular grooves34 a can be 1.5 times or more and less than 2 times the number of theplurality of long holes 24.

In this regard, after screwing the tap part 21 of the flange 20 to thetap part 14 of the ball valve 10, when coupling the housing 30 to theflange 20 using the fastening member 50, even if the rotational phase ofthe flange 20 is different, the flange 20 can be smoothly fastened tothe flange coupling part 34 of the housing 30.

In some implementations, the rotational phase of the flange 20 may varydepending on the starting point of a thread provided in the tap part ofthe ball valve.

In some implementations, a distance D1 between the two adjacent longholes 24 can be less than a distance D2 between the two adjacentcircular grooves 34 a.

In some implementations, a bridge 27 is positioned between the twoadjacent long holes 24, and the width of the bridge 27, that is, thedistance D1 between the two adjacent long holes 24 can be less than thelength L of the long holes 24.

Thus, the strength of the flange 20 can be maintained due to the bridge27.

The housing 30 can have a power line passage hole 44 through which anexternal power line 42 for supplying power to the motor 40 passes, andan adhesive 46 can be applied to the power line passage hole 44 in astate where the external power line 42 passes through.

The power line passage hole 44 can be defined in the lower case 31 orthe upper case 32.

In some implementations, one power line passage hole 44 may be partiallydefined in each of the lower case 31 and the upper case 32, and it maybe defined as a whole in a state in which the lower case 31 and theupper case 32 are coupled.

The adhesive 46 applied to the power line passage hole 44 can blockmoisture from entering the inside of the housing 30 through the powerline passage hole 44.

To block the adhesive 46 applied to the power line passage hole 44 frombeing separated and/or detached from the housing 30, the inner surfaceof the housing 30 around the power line passage hole 44 can be providedwith an adhesive receiving groove 48 provided to be larger than thepower line passage hole 44 and in which a portion of the adhesive 46 ispositioned.

Therefore, the adhesive 46 applied to the power line passage hole 44 canbe blocked from being separated and/or detached from the power linepassage hole 44.

A seating part 31 a on which a protruding jaw 33 a of the middle plate33 is seated can be provided at an upper end of the lower case 31 of thehousing 30.

In some implementations, a first seal ring R1 is disposed on the seatingpart 31 a of the lower case 31.

The first seal ring R1 can be supported by a lower end of the upper case32, the seating part 31 a of the lower case 31, and the protruding jaw33 a of the middle plate 33, respectively.

In some implementations, the first seal ring R1 is pressed in thevertical (Y-Y′) direction by the upper case 32 and the lower case 31.

In addition, the first seal ring R1 can be pressed in the horizontal(X-X′) direction by the protruding jaw 33 a of the middle plate 33 andthe seating part 31 a of the lower case 31, or supported in thehorizontal (X-X′) direction by the protruding jaw 33 a of the middleplate 33 and the seating part 31 a of the lower case 31.

Therefore, when the upper case 32 and the lower case 31 contract andexpand due to the temperature difference during use of the valveactuator, it is possible to prevent airtightness from deteriorating dueto a minute gap between the upper case 32 and the lower case 31.

The motor 40 and the gear assembly 100 can be disposed in a spaceprovided by the lower case 31 and the middle plate 33 in the inner spaceof the housing 30.

In some implementations, the motor 40 may be disposed in a spaceprovided by the middle plate 33 and the upper case 32, such that thearrangement of the plurality of gears provided in the gear assembly 100may be different.

When the motor 40 and the gear assembly 100 are disposed in the spaceprovided by the lower case 31 and the middle plate 33 in the inner spaceof the housing 30, the length of the rotational shaft of the motor 40and the shaft coupled to the gears of the gear assembly 100 may beformed short, and the size of the space occupied by the middle plate 33and the upper case 32 can be reduced. Accordingly, the size of the valveactuator can be reduced.

The motor 40 may be a type of motor with precise rotational control. Insome implementations, the motor 40 may a type of motor with impreciserotational control. In addition, the motor 40 can be a normal/reverserotation motor.

The gear assembly 100 can include an input gear 110 coupled to arotational shaft 41 of the motor 40 and rotating together with therotational shaft 41, and an output gear 120 spaced apart from the inputgear 110 in the horizontal (X-X′) direction.

The gear assembly 100 can further include power transmission gears 130and 140 that transmit the rotational force of the input gear 110 to theoutput gear 120.

The output gear 120 can be coupled to the stem 16 of the ball valve 10and transmit the rotational force of the input gear 110 to the stem 16of the ball valve 10.

In some implementations, the power transmission gear includes a firstgear set 130 and a second gear set 140 disposed adjacent to the firstgear set 130 in the horizontal (X-X′) direction.

The first gear set 130 can include a clutch shaft 131 having both endscoupled to the middle plate 33 and the lower case 31 so as to be movablein the vertical (Y-Y′) direction.

In addition or alternatively, the first gear set 130 can further includea first gear 133 and a second gear 135 that are coupled to the clutchshaft 131 and disengaged from each other or coupled to each other by themovement of the clutch shaft 131 in the vertical (Y-Y′) direction.

The clutch shaft 131 and the first gear set 130 can constitute a clutchunit in the valve actuator.

If the clutch unit is not operated in a state in which the motor 40 isdriven and the ball valve 10 blocks the flow of refrigerant, when tryingto return the ball valve 10 to its original position (a position whererefrigerant can flow) in a state where the gears of the gear assemblyare meshed with each other, there is a possibility that the teeth of thegears provided in the gear assembly may be damaged.

In order to solve this problem, a clutch unit can be provided in thevalve actuator.

In the conventional valve actuator, the clutch unit is installed on theoutput shaft of the gear assembly.

Therefore, since the output shaft moves in two directions, a rotationaldirection and a vertical (Y-Y′) direction, there is a problem in thatsealing performance is deteriorated, and since the output shaft has tomove in the vertical (Y-Y′) direction, there is a problem in that thesize of the product increases.

In addition, since a large rigid return spring is required to return theoutput shaft, and the engagement between the gear teeth is directlydisengaged, there is a problem in that gear teeth are adverselyaffected.

However, according to implementations of the clutch unit, since themiddle shaft (shaft of the power transmission gear) of the gear train,not the output shaft, is provided as the clutch shaft 131, the clutchshaft 131 can be operated with less force compared to the case where theoutput shaft is used as the clutch shaft.

In addition, since the first gear 133 and the second gear 135 may becoupled or disengaged according to the movement of the clutch shaft 131in the vertical (Y-Y′) direction, when the clutch shaft 131 is operated,coupling between gears can be disengaged, not disengagement of couplingbetween gear teeth.

Therefore, when the clutch shaft 131 moves in the vertical (Y-Y′)direction, the influence on the teeth of the input gear 110, the outputgear 120, and the power transmission gears 130 and 140 can be minimized.

A coupling part 133 a for coupling the first gear 133 to the second gear135 can protrude from the lower surface of the first gear 133 coupled tothe input gear 110.

In some implementations, a coupling part insertion groove 135 a intowhich the coupling part 133 a of the first gear 133 is inserted can beprovided on the upper surface of the second gear 135.

The coupling part 133 a and the coupling part insertion groove 135 a mayhave shapes corresponding to each other.

In some implementations, the coupling part 133 a can have a planar shapeand the coupling part insertion groove 135 a can have a spline shape. Insome implementations, the coupling part 133 a and the coupling partinsertion groove 135 a can have various shapes such as an ellipse or apolygon.

When the coupling part 133 a of the first gear 133 is inserted into thecoupling part insertion groove 135 a of the second gear 135, the heightor thickness of the first gear set 130 in the vertical (Y-Y′) directioncan be reduced.

Accordingly, since the size of the space occupied by the middle plate 33and the lower case 31 can be reduced, the size of the valve actuator canbe reduced.

A push-up part 131 a can be provided on the clutch shaft 131 to push thefirst gear 133 upward in contact with the coupling part 133 a of thefirst gear 133.

In addition, a push-up part insertion groove 133 b can be provided onthe lower surface of the coupling part 133 a of the first gear 133.

Therefore, the push-up part 131 a of the clutch shaft 131 can beinserted into the push-up part insertion groove 133 b provided on thelower surface of the coupling part 133 a of the first gear 133.

When the push-up part 131 a of the clutch shaft 131 is inserted into thepush-up part insertion groove 133 b provided on the lower surface of thecoupling part 133 a of the first gear 133, the height or thickness ofthe first gear set 130 in the vertical (Y-Y′) direction can be reduced.

Therefore, since the size of the space occupied by the middle plate 33and the lower case 31 can be further reduced, the size of the valveactuator can be further reduced.

A return spring 137 can be disposed on the clutch shaft 131 above thefirst gear 133.

In some implementations, the first gear 133 can be pressed toward thesecond gear 135 by the return spring 137.

In this regard, the first gear 133 and the second gear 135 can becoupled to each other between the gears before the valve actuatoroperates.

For example, before the operation of the valve actuator, since thecoupling part 133 a of the first gear 133 is coupled to the couplingpart insertion groove 135 a of the second gear 135, the first gear 133and the second gear 135 can be coupled to each other between the gears.

In addition, after the operation of the valve actuator when the clutchshaft 131 is pressed from the bottom to the top to return the ball valveto its original position, while the return spring 137 is pressed, thefirst gear 133 can be pushed up by the push-up part 131 a, andaccordingly, the coupling between the first gear 133 and the second gear135 can be disengaged.

In some implementations, when pressing of the clutch shaft 131 isdisengaged while rotating the output shaft 121 by inserting a tool suchas a screwdriver into a groove provided at the upper end of the outputshaft 121, the first gear 133 can be pressed downward by the returnspring 137.

Therefore, while the output shaft 121 of the output gear 120 rotates andthe coupling part 133 a of the first gear 133 is inserted into thecoupling part insertion groove 135 a of the second gear 135, the firstgear 133 and the second gear 135 can be coupled again.

A snap ring 139 can be installed on the clutch shaft 131 between thereturn spring 137 and the upper surface of the first gear 133.

The snap ring 139 can be provided on the clutch shaft 131 to allow theclutch shaft 131 to be manually pulled in case the clutch shaft 131 doesnot return to the original position due to the malfunction of the returnspring 137.

Therefore, when the first gear 133 does not move downward due to themalfunction of the return spring 137 despite the disengagement of thepressing of the clutch shaft 131, when the clutch shaft 131 is pulleddownward, the snap ring 139 can move downward together with the clutchshaft 131, so that the coupling part 133 a of the first gear 133 can becoupled to the coupling part insertion groove 135 a of the second gear135.

A third seal ring R3 can be disposed on the clutch shaft below thesecond gear 135.

In the lower case 31 where the clutch shaft 131 is coupled when theclutch shaft 131 moves in the vertical (Y-Y′) direction, a guide groove31 a can be provided to guide the third seal ring R3 to move in thevertical (Y-Y′) direction together with the clutch shaft 131, the guidegroove 31 a can extend to the inner surface of the lower case 31.

Therefore, the moving distance of the clutch shaft 131 in the upwarddirection can be set by a distance D3 between the third seal ring R3 andthe second gear 135.

In this regard, by appropriately setting the distance D3 between thethird seal ring R3 and the second gear 135, the moving distance of theclutch shaft 131 in the upward direction can be adjusted.

In the state where the coupling between the gears of the first gear 133and the second gear 135 is disengaged, the second gear 135 may besupported by the third seal ring R3 and/or the lower case 31.

Therefore, in the state where the coupling between the gears of thefirst gear 133 and the second gear 135 is disengaged, the downwardmovement of the second gear 135 can be limited by the third sea ring R3and/or the lower case 31.

In some implementations, when the second gear 135 is spaced apart fromthe inner surface of the lower case 31 by a certain distance, a separatesupport shaft for supporting the second gear 135 outside the clutchshaft 131 can be provided.

In this regard, in a state where the coupling between the gears of thefirst gear 133 and the second gear 135 is disengaged, the downwardmovement of the second gear 135 may be limited by a separate supportshaft.

In addition, if a part of the second gear 135 is positioned below themotor 40 and a third gear 141, when disengaging the coupling between thegears of the first gear 133 and the second gear 135, the upward movementof the second gear 135 may be limited by the motor 40 and the secondgear set 140.

The second gear set 140 can be disposed adjacent to the first gear set130 in the horizontal (X-X′) direction.

The second gear set 140 can be coupled to the first gear 133 and includethe third gear 141 in which a part of the second gear 135 is positionedat the lower portion.

In some implementations, the second gear set 140 can be positioned abovethe third gear 141 and can further include a fourth gear 143 thatrotates integrally with the third gear 141 and is coupled to the outputgear 120.

The third gear 141 and the fourth gear 143 constituting the second gearset 140 may be formed as one body, or may be manufactured separately andcoupled between gears with a structure similar to that of the first andsecond gears 133 and 135.

In some implementations, since the power transmission gear includes thefirst gear set 130 and the second gear set 140, the structure of thegear assembly 100 can be simplified.

The lower end of the output shaft 121 coupled with the output gear 120can be coupled to the stem 16 of the ball valve 10, and the upper end ofthe output shaft 121 can protrude to an outside of the upper case 32.

In addition, a fourth seal ring R4 can be disposed between the outputshaft 121 and the lower case 31 between the lower end of the outputshaft 121 and the output gear 120.

In some implementations, the refrigerant flowing along the ball valve 10can be blocked from entering the inside of the valve actuator through aminute gap provided between the output shaft 121 and the lower case 31.

A fifth seal ring R5 can be disposed between the output shaft 121 andthe upper case between the upper end of the output shaft 121 and theoutput gear 120.

In some implementations, moisture can be blocked from entering theinside of the housing 30 through a minute gap provided between the uppercase 32 and the output shaft 121.

In the upper case 32, a cap R6 covering the upper end of the outputshaft 121 protruding out of the upper case 32 can be installed.

In addition, the cap R6 can cover the minute gap between the outputshaft 121 and the upper case 32.

In some implementations, moisture can be more effectively blocked fromentering the inside of the housing 30 through the minute gap providedbetween the upper case 32 and the output shaft 121.

In the above, the valve actuator for controlling the ball valve providedin the air conditioning system has been described, but the valveactuator of the present disclosure can be applied to other valves forcontrolling a flow path of gas or fluid.

What is claimed is:
 1. A valve actuator comprising: a housing definingan inner space; a motor disposed in the inner space of the housing; anda gear assembly disposed in the inner space of the housing andconfigured to transmit, to a ball valve, a driving force of the motor,wherein the gear assembly includes: an input gear coupled to arotational shaft of the motor and configured to rotate with therotational shaft, an output gear spaced apart from the input gear in ahorizontal direction, coupled to a stem of the ball valve, andconfigured to transmit a rotational force of the input gear to the stem,and a power transmission gear configured to transmit the rotationalforce of the input gear to the output gear, wherein the powertransmission gear includes a first gear set disposed between the inputgear and the output gear, and wherein the first gear set includes: aclutch shaft disposed in the housing and configured to move in avertical direction, and a first gear and a second gear that are coupledto the clutch shaft and that are configured to, based on verticalmovement of the clutch shaft, disengage from or couple to each other. 2.The valve actuator of claim 1, wherein the first gear provides acoupling part configured to couple the first gear to the second gear andprotruding from a lower surface of the first gear coupled to the inputgear, and wherein an upper surface of the second gear provides acoupling part insertion groove into which the coupling part of the firstgear is inserted.
 3. The valve actuator of claim 2, wherein the clutchshaft provides a push-up part that is configured to push the first gearupward by contacting the coupling part of the first gear and that ispositioned in a push-up part insertion groove provided at a lowersurface of the coupling part of the first gear.
 4. The valve actuator ofclaim 3, wherein the housing includes: a lower case, an upper casecoupled to the lower case, and a middle plate positioned in a spacedefined by the lower case and the upper case, and wherein the motor andthe gear assembly are disposed in a space defined by the middle plateand the lower case.
 5. The valve actuator of claim 4, wherein the firstgear is configured to move toward the second gear by a return springdisposed between the first gear and the middle plate.
 6. The valveactuator of claim 5, further comprising a snap ring disposed at theclutch shaft and between the return spring and an upper surface of thefirst gear.
 7. The valve actuator of claim 6, further comprising a sealring disposed at the clutch shaft and below the second gear, wherein thelower case provides a guide groove at which the clutch shaft is coupledand configured to, based on the clutch shaft moving in the verticaldirection, allow the seal ring to move in the vertical direction withthe clutch shaft.
 8. The valve actuator of claim 7, wherein a movementdistance of the clutch shaft in an upward direction is based on a gapbetween the seal ring and the second gear.
 9. The valve actuator ofclaim 8, wherein the power transmission gear further includes a secondgear set disposed adjacent to the first gear set in the horizontaldirection, and wherein the second gear set includes: a third gearcoupled to the first gear, and a fourth gear disposed above the thirdgear, configured to rotate with the third gear, and coupled to theoutput gear.
 10. The valve actuator of claim 9, wherein the motor andthe third gear are configured to, based on the clutch shaft movingupward, limit an upward movement of the second gear.
 11. A valveactuator comprising: a housing defining an inner space; a motor disposedin the inner space of the housing; and a gear assembly disposed in theinner space of the housing and configured to transmit, to a ball valve,a driving force of the motor, wherein the gear assembly includes: aninput gear coupled to a rotational shaft of the motor and configured torotate with the rotational shaft, an output gear spaced apart from theinput gear in a horizontal direction, coupled to a stem of the ballvalve, and configured to transmit a rotational force of the input gearto the stem, and a power transmission gear configured to transmit therotational force of the input gear to the output gear, wherein the powertransmission gear includes a first gear set and a second gear setdisposed between the input gear and the output gear and arranged alongthe horizontal direction.
 12. The valve actuator of claim 11, whereinthe first gear set includes: a clutch shaft disposed in the housing andconfigured to move in a vertical direction, and a first gear and asecond gear that are coupled to the clutch shaft and that are configuredto, based on vertical movement of the clutch shaft, disengage from orcouple to each other.
 13. The valve actuator of claim 12, wherein thefirst gear provides a coupling part configured to couple the first gearto the second gear and protruding from a lower surface of the first gearcoupled to the input gear, and wherein an upper surface of the secondgear provides a coupling part insertion groove into which the couplingpart of the first gear is inserted.
 14. The valve actuator of claim 13,wherein the clutch shaft provides a push-up part that is configured topush the first gear upward by contacting the coupling part of the firstgear and that is positioned in a push-up part insertion groove providedat a lower surface of the coupling part of the first gear.
 15. The valveactuator of claim 14, wherein the housing includes: a lower case, anupper case coupled to the lower case, and a middle plate positioned in aspace defined by the lower case and the upper case, and wherein themotor and the gear assembly are disposed in a space defined by themiddle plate and the lower case.
 16. The valve actuator of claim 15,wherein the first gear is configured to move toward the second gear by areturn spring disposed between the first gear and the middle plate. 17.The valve actuator of claim 16, further comprising a snap ring disposedat the clutch shaft and between the return spring and an upper surfaceof the first gear.
 18. The valve actuator of claim 17, furthercomprising a seal ring disposed at the clutch shaft and below the secondgear, Wherein the lower case provides a guide groove at which the clutchshaft is coupled and configured to, based on the clutch shaft moving inthe vertical direction, allow the seal ring to move in the verticaldirection with the clutch shaft.
 19. The valve actuator of claim 18,wherein a movement distance of the clutch shaft in an upward directionis based on a gap between the seal ring and the second gear.
 20. Thevalve actuator of claim 12, wherein the second gear set includes: athird gear coupled to the first gear, and a fourth gear disposed abovethe third gear, configured to rotate with the third gear, and coupled tothe output gear, and wherein the motor and the third gear are configuredto, based on the clutch shaft moving upward, limit an upward movement ofthe second gear.